Navy contributes underwater technology to jet search

Apr. 4, 2014
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An observer watches as a smoke flare is deployed to mark an unidentified object spotted from a RNZAF P3 Orion during search operations for wreckage and debris of missing Malaysia Airlines Flight MH370 in Southern Indian Ocean on Friday, near Australia. Up to fourteen planes and nine ships resumed in the search for missing Malaysia Airlines flight MH370 in the Indian Ocean off the coast of Western Australia today. The airliner disappeared on March 8 with 239 passengers and crew on board and is suspected to have crashed into the southern Indian Ocean. / Pool Getty Images

by Bart Jansen, USA TODAY

by Bart Jansen, USA TODAY

Two pieces of Navy equipment were added to the underwater search for the missing Malaysia Airlines jet Friday, one for sound and one for visual images.

Search experts warned that the equipment moves slowly and covers a small area. Searching hundreds of thousands of square miles of Indian Ocean for wreckage from Flight 370, which has been missing since March 8, remains a difficult task.

"These are very slow, with a very limited range," said Alan Diehl, a former investigator with the National Transportation Safety Board. "It's been compared to looking for an object on a football field by viewing it through a soda straw."

Despite the challenges, the search is urgent. The jet's data and voice recorders are certified to send out signals for 30 days after coming into contact with water, although they can last a couple of weeks longer, depending on conditions.

The so-called pingers on the jet's recorders send a signal that can be picked up by sonar within 2 miles, although the distance is diminished by uneven topography on the ocean floor or if muffled by the jet's wreckage

Search planes have dropped buoys to listen for a signal. If the ocean is more than 2 miles deep at the spot where the buoys float, they could miss a signal even if they were right above the wreckage.

The advantage the two types of Navy technology provide is that they can swim deeper.

The towed pinger locator, called a TPL-25, is lowered by cable behind a ship and kept about 1,000 feet above the ocean floor, according to the Navy. The locator can hear a signal about 1 mile away and to a depth of 20,000 feet.

The ship towing the locator can generally move 3 to 6 mph to search about 150 square miles per day, the Navy said. Search planes coordinated by Australia have been covering 100,000 square miles, an area as large as Oregon.

Another piece of Navy equipment is the Bluefin-21, an unmanned underwater vehicle 16 feet long and 21 inches in diameter, weighing 1,650 pounds. It is certified to go 14,763 feet deep.

The submersible can travel up to 5 mph to scan the ocean floor with sonar and camera. The Navy hopes to scan about 40 square miles per day with the submersible.

The locators work optimally in a small search area, Marine Lt. Col. Jeff Pool, a Pentagon spokesman, said Friday. They work slowly and in tandem: The pinger locator detects the target; and the small, unmanned submarine maps the seafloor, Pool said.

The pinger locator and the Bluefin-21 are hindered by bad weather on the surface. The pinger locator helped find a Marine AV-8B Harrier that crashed in the Gulf of Oman in 2011. The Bluefin-21 helped recover an Air Force F-15 off the coast of Japan.

Diehl said it is important to find a signal from the Malaysia jet before its recorders stop sending their emergency transmissions in the next week or two.

"It's an extremely large ocean. The chances of finding anything once the pingers die is going to be unlikely," Diehl said. "This is the kind of thing where you can put away the stopwatch and get out the calendar because it could be months or years."